The fermentation and drying of manure are essential processes for transforming it into a stable organic fertilizer, free of unpleasant odors and with a high nutrient content.

1. Manure fermentation (Fermentation methods)

Fermentation is the process by which organic matter is broken down by microorganisms, transforming manure into mature compost.

1. Aerobic fermentation (composting)

Description: Takes place in the presence of oxygen through the activity of aerobic bacteria.

Process:

• Manure is placed in piles, platforms, or composting tunnels.
• Aeration is ensured by periodically turning the material.
• The temperature reaches 50–70°C, destroying pathogens and weed seeds.
• The duration is 4–8 weeks.

Advantages:

• ✅ Destroys pathogens and unpleasant odors.
• ✅ Fast and efficient process.
• ✅ Improves soil structure and fertility.

2. Anaerobic fermentation (anaerobic digestion)

Description: Occurs in the absence of oxygen and is used for biogas production.

Process:

• Carried out in closed biodigesters.
• The material is decomposed by methanogenic bacteria, producing biogas (CH₄ + CO₂) and digestate (liquid or solid fertilizer).
• The optimal temperature is 35–55°C (mesophilic or thermophilic).
• The duration is 30–90 days.

Advantages:

• ✅ Produces biogas usable for energy.
• ✅ Reduces greenhouse gas emissions.
• ✅ The resulting digestate is a valuable fertilizer.

3. Controlled fermentation with effective bacteria (EM – Effective Microorganisms)

Description: Beneficial bacteria are used for rapid and odor-free fermentation.

Process:

• Solutions containing lactobacilli, yeasts, and photosynthetic bacteria are added to the manure.
• Optimal moisture and controlled temperature are maintained.
• A mature compost is obtained in 2–4 weeks.

Advantages:

• ✅ Faster process than classic composting.
• ✅ Reduces ammonia and hydrogen sulfide emissions.
• ✅ Enriches the soil with beneficial microorganisms.

4. Thermophilic fermentation

Description: Takes place at high temperatures (50–70°C), rapidly destroying pathogens.

Process:

• Manure is maintained at high temperatures for 7–14 days.
• Requires strict control of aeration and moisture.

Advantages:

• ✅ Very fast process.
• ✅ Eliminates odors and pathogens.
• ✅ Ideal for the production of certified organic compost.

5. Cold fermentation (slow decomposition)

Description: A natural process without intervention, carried out at low temperatures.

Process:

• Manure is left to decompose naturally over a long period (6–12 months).
• Aeration is minimal, and the temperature does not exceed 30–40°C.

Advantages:

• ✅ Simple process with no costs.
• ✅ Better preserves soluble nutrients.
• ✅ Does not require special equipment.

Disadvantages:

• ❌ Long duration.
• ❌ Risk of nitrogen loss through volatilization.

2. Manure drying

Drying is necessary to reduce moisture content and prevent rapid material degradation.

Drying methods

Natural drying

• Performed by exposure to sunlight on specially designed platforms.
• Requires periodic turning for uniform drying.
• Slower process, affected by weather conditions.

Mechanical drying

• Uses rotary dryers, conveyor belts with hot air, or fluidized bed dryers.
• Reduces moisture to 10–15%, accelerating the process compared to natural drying.
• Allows production of fertilizer in powder, granule, or pellet form.

Advantages of manure fermentation and drying

• ✅ Eliminates unpleasant odors and pathogens.
• ✅ Reduces volume and weight, facilitating transport and storage.
• ✅ Improves nutritional value, providing a stable and efficient fertilizer.
• ✅ Allows the use of biogas as an energy source in the case of anaerobic fermentation.